Systems and methods for processing vapor

ABSTRACT

A system for processing vapor. The system includes a vapor source for producing a vapor and an outlet conduit coupled to the vapor source for carrying the vapor from the vapor source. Downstream of the vapor source the outlet conduit separates into a vapor bypass conduit and a vapor feed conduit. The system further includes a first vapor control valve disposed in the bypass conduit, a second vapor control valve disposed in the feed conduit, a first vacuum chamber connected to the bypass conduit, and a second vacuum chamber connected to the feed conduit.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a divisional filing of U.S. Ser. No. 14/232,671, filed Jan. 14,2014, now allowed, which is a national stage filing under 35 U.S.C. 371of PCT/US2012/049146, filed Aug. 1, 2012, which claims priority to U.S.Provisional Application No. 61/515,399 filed Aug. 5, 2011, thedisclosures of which are incorporated by reference in their entiretyherein.

FIELD

The present disclosure relates to systems and methods for processingvapor and, particularly, to systems and methods for monitoring andcontrolling a flow of vapor generated by a vapor source.

BACKGROUND

Vapor coating techniques such as plasma deposition and chemical vapordeposition are used to deposit thin coatings of various materialswithout the use of solvents. Processes for coating organic materialsonto a substrate (e.g., polymerizable or curable materials) bycondensing a vapor containing such a material onto a substrate (e.g., apolymer film) and polymerizing and/or curing the condensed material areknown, e.g., U.S. Pat. No. 4,842,893. These processes can involve theevaporation of organic or organometallic precursors to create a vaporthat is transferred to the substrate to be coated. Some patents relatedto evaporation methods and apparatus are U.S. Pat. Nos. 6,309,508 and7,112,351.

SUMMARY

In a first aspect, a system for processing vapor is provided. The systemmay include a vapor source for producing a vapor and an outlet conduitcoupled to the vapor source for carrying the vapor from the vaporsource. Downstream of the vapor source the outlet conduit may separateinto a vapor bypass conduit and a vapor feed conduit. The system mayfurther include a first vapor control valve disposed in the bypassconduit, a second vapor control valve disposed in the feed conduit, afirst vacuum chamber fluidically coupled to the bypass conduit, and asecond vacuum chamber fluidically coupled to the feed conduit.

In another aspect, a method for processing vapor is provided. The methodmay include discharging a vapor from a vapor source into a fluidpathway. The fluid pathway may include an outlet conduit fluidicallycoupled to the vapor source. Downstream of the vapor source the outletconduit may separate into a vapor bypass conduit and a vapor feedconduit. The fluid pathway may further include a first vapor controlvalve disposed in the bypass conduit and a second vapor control valvedisposed in the feed conduit, a first vacuum chamber fluidically coupledto the bypass conduit, and a second vacuum chamber fluidically coupledto the feed conduit. The method may further include controlling anamount of vapor passing through the feed conduit and the bypass conduitvia manipulation of either or both of the first vapor control valve andthe second vapor control valve.

The above summary of the present disclosure is not intended to describeeach embodiment of the present invention. The details of one or moreembodiments of the disclosure are also set forth in the descriptionbelow. Other features, objects, and advantages of the invention will beapparent from the description and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure may be more completely understood in consideration of thefollowing detailed description of various embodiments of the disclosurein connection with the accompanying figures, in which:

FIG. 1 illustrates a schematic diagram of a system for processing vaporin accordance with some embodiments of the present disclosure.

FIG. 2 is a plot of mean coated thickness as a function of mean vaporpressure, which was generated using systems and methods in accordancewith some embodiments of the present disclosure.

FIG. 3 is a plot of both vapor pressure and measured coated thickness,as a function of substrate web position, which was generated usingsystems and methods in accordance with some embodiments of the presentdisclosure.

DETAILED DESCRIPTION

Vapor coating techniques such as, for example, chemical vapor deposition(CVD), plasma deposition, and polymer multi-layer deposition are used todeposit thin coatings of various materials on a substrate without theuse of solvents. Often times, these techniques require the evaporationof a material (e.g., an organic, organometallic, or metal) to create avapor flow to a deposition appliance (e.g., nozzle), which is positionedproximate the substrate to be coated.

Current evaporation processes utilized in such vapor coating techniquesare known to produce unstable and variable evaporation rates over time.Moreover, in current vapor coating systems, the rate of deposition ontothe substrate is a function of the rate of evaporation. Consequently,instability in evaporation rates leads to variation over time indeposition rate and, in turn, coating thickness.

The present disclosure relates to systems and methods for monitoring andcontrolling the characteristics of a vapor flow produced by a vaporsource (e.g., an evaporator). In some embodiments, the systems andmethods may involve monitoring and controlling a flow of vapor generatedby a vapor source, which is to be deposited as a coating onto asubstrate in a vapor coating chamber, such that a rate of vaporproduction in the vapor source (e.g., evaporation rate) is decoupledfrom a deposition rate of the vapor in the vapor coating chamber. Inthis manner, the systems and methods of the present disclosure mayaccount for perturbations in vapor flow caused by variable vaporgeneration rates, thereby enabling precise control of vapor depositionrates and coating thickness.

As used in this specification and the appended embodiments, the singularforms “a”, “an”, and “the” include plural referents unless the contentclearly dictates otherwise.

As used in this specification and the appended embodiments, the term“or” is generally employed in its sense including “and/or” unless thecontent clearly dictates otherwise.

As used in this specification, the recitation of numerical ranges byendpoints includes all numbers subsumed within that range (e.g. 1 to 5includes 1, 1.5, 2, 2.75, 3, 3.8, 4, and 5).

Unless otherwise indicated, all numbers expressing quantities oringredients, measurement of properties and so forth used in thespecification and embodiments are to be understood as being modified inall instances by the term “about.” Accordingly, unless indicated to thecontrary, the numerical parameters set forth in the foregoingspecification and attached listing of embodiments can vary dependingupon the desired properties sought to be obtained by those skilled inthe art utilizing the teachings of the present disclosure. At the veryleast, and not as an attempt to limit the application of the doctrine ofequivalents to the scope of the claimed embodiments, each numericalparameter should at least be construed in light of the number ofreported significant digits and by applying ordinary roundingtechniques.

Various exemplary embodiments of the disclosure will now be describedwith particular reference to the Drawings. Exemplary embodiments of thepresent disclosure may take on various modifications and alterationswithout departing from the spirit and scope of the disclosure.Accordingly, it is to be understood that the embodiments of the presentdisclosure are not to be limited to the following described exemplaryembodiments, but are to be controlled by the limitations set forth inthe claims and any equivalents thereof.

FIG. 1 illustrates a schematic diagram of a system 2 for processingvapor in accordance with some embodiments of the present disclosure. Thesystem may include a vapor source 4 fluidically coupled, via a fluidpathway 6, to a first vacuum chamber 8 and a second vacuum chamber 12.The fluid pathway 6 may include an outlet conduit 6 a, a vapor bypassconduit 6 b, and a vapor feed conduit 6 c. A pressure sensor 14 may beoperatively coupled to the fluid pathway 6. A vapor bypass control valve16 and a vapor feed control valve 18 may be disposed in the vapor bypassconduit 6 b and the vapor feed conduit 6 c, respectively. The system mayfurther include a controller 22 operatively coupled to the pressuresensor 14 and either or both of the bypass vapor control valve 16 andthe feed vapor control valve 18.

In some embodiments, the vapor source 4 may be configured as any devicecapable of vaporizing liquid. Suitable vapor sources may include, forexample, heated baths, bubblers, atomizers, cyclone evaporators,ultrasonic evaporators, wiped-film evaporators, rolled film evaporators,spinning disk evaporators, rotary evaporators, porous frit evaporators,tubular evaporators, and the like. In various embodiments, the vaporsource 4 may include one or more of the vapor sources described in thefollowing patents and publications, incorporated by reference herein intheir entireties: U.S. Pub. No. 2008/0108180 (Charles, et al.); U.S.Pub. No. 2008/0292810 (Anderson, et al.); U.S. Pat. No. 7,300,538 (Lemmeet al.); U.S. Pat. No. 6,245,150 (Lyons et al.); U.S. Pat. No. 4,954,371(Yializis et al.); U.S. Pat. No. 5,653,813 (Benzing et al.); U.S. Pat.No. 5,595,603 (Klinedinst et al.); U.S. Pat. No. 5,536,323 (Kirlin etal.); U.S. Pat. No. 5,431,736 (Boer et al.); U.S. Pat. No. 5,356,451(Cain et al.); U.S. Pat. No. 5,558,687 (Cain et al.); U.S. Pat. No.5,951,923 (Horie et al.); U.S. Pub. No. 2008/0017110 (Kim et al.); U.S.Pub. No. 2007/0120275 (Liu et al.); U.S. Pat. No. 6,089,548 (Plitzner etal.); U.S. Pat. No. 6,157,774 (Komino et al.); U.S. Pat. No. 6,958,107(Clarke et al.); U.S. Pat. No. 6,409,839 (Sun et al.); and U.S. Pat. No.6,488,985 (Honda et al.). While the present disclosure is described withrespect to a single vapor source 4, it is to be appreciated that anynumber of additional vapor sources may be utilized. For example, aplurality of vapor sources 4 may be useful in embodiments in which avapor mixture is desired and vaporization of two or more components ofthe vapor mixture in a single vapor source is difficult or impracticable(e.g., due to varying vapor pressure curves, immiscibility of thecomponents in a liquid state, or undesirable reactions of components inliquid state).

In illustrative embodiments, the vapor supplied by the vapor source 4may include monomers, oligomers, resins, waxes, solvents, organiccompounds, organometallic compounds, metallic compounds, biologicallyactive materials, and combinations thereof. Other suitable materials forvaporization include, but are not limited to, epoxies, vinyl ethers,(meth)acrylates, fluoro-containing polymers, styrene containingpolymers, acetylenes, polyamides, acrylamides, parylenes, waxes,fluoropolyethers, polyamines, diallyldiphenylsilanes, metal alkoxides,metal alkyls, silicones, oils, dyes, proteins, peptides, polypeptides,lipids, carbohydrates, enzymes, nucleic acids, polynucleic acids, drugs,drug metabolites, and combinations thereof.

In various embodiments, the vapor supplied by the vapor source 4 (and/orliquids or solids supplied as inputs to the vapor source 4) may includeone or more additives to affect processing of the vapor and/or theproperties and performance of a condensed or deposited material formedfrom the vapor, as is known in the art. For example, one or moreadditives may be included to lower surface tension, reduce viscosity,inhibit thermally-induced reactions such as polymerization, preventoxidation reactions, or combinations thereof. To impart desirableproperties in a condensed or deposited material formed from the vaporsupplied by the vapor source 4, one or more additives may be included toabsorb radiation (e.g., UV, visible wavelengths, IR, and microwaveenergy) and/or initiate reactions (e.g., photoinitiators, thermalinitiators, and the like). Other additives may include colorants,crosslinkers, or other materials known in the art.

In some embodiments, combination of one or more reactive and/ornon-reactive gases with the vapor generated by the vapor source 4 may beappropriate. In this regard, the system 2 may include a gas source 24configured to provide a flow of gas to the vapor source 4 and/or theflow pathway 6. Suitable inert gases may include nitrogen, argon,helium, neon, and combinations thereof. Suitable reactive gases mayinclude oxygen, ozone, nitrous oxide, hydrogen, hydrogen sulfide, carbontetrafluoride, methane, ammonia, and combinations thereof.

In various embodiments, the vapor source 4 (and optionally the gassource 24) may be fluidically coupled to a fluid pathway 6. The fluidpathway 6 may include an outlet conduit 6 a, which is fluidicallycoupled on a first end to the vapor source 4, and which is bifurcated ona second end to separate flow from the outlet conduit 6 a into a vaporbypass conduit 6 b and a vapor feed conduit 6 c. The vapor bypassconduit 6 b may terminate in a fluidic coupling to the first vacuumchamber 8. The vapor feed conduit 6 c may terminate in a fluidiccoupling to the second vacuum chamber 12.

In some embodiments, one or more pressure sensors may be operativelyassociated with the fluid pathway 6. The pressure sensors may bepositioned and configured to sense a pressure of fluid being transportedthrough the fluid pathway 6. For example, the system 2 may include apressure sensor 14 positioned to sense the pressure of fluid beingtransported through the outlet conduit 6 a. Additionally, oralternatively, the system may include pressure sensors positioned ineither or both of the vapor bypass conduit 6 b and feed conduit 6 c, forexample, downstream of the vapor bypass control valve 16 and the vaporfeed control valve 18, respectively.

In some embodiments, a bypass vapor control valve 16 and a feed vaporcontrol valve 18 may be disposed in the vapor bypass conduit 6 b and thevapor feed conduit 6 c, respectively. Generally, the valves 16, 18 maybe configured as any devices capable of fully or partially opening orclosing such that one of more properties (e.g., rate, pressure) of afluid flow passing therethrough may be adjusted. The degree to which thevalves are opened/closed, which may be referred to herein as “theposition” of the valve, may be adjusted manually, or automatically, suchas in response to signals received from the controller 22. Theadjustment of the position of the valves 16, 18 may be carried out bymeans of mechanical, electrical, hydraulic, or pneumatic systems, orcombinations thereof. In one embodiment, the valves 16, 18 may besubstantially similar. For example, each of the valves 16, 18 may beconfigured such that their respective valve positions may becontinuously adjustable between a fully open and a fully closed position(hereinafter, a “continuously adjustable control valve”). In anotherembodiment, the valves 16, 18 may of different construction. Forexample, the bypass control valve 16 may be a continuously adjustablecontrol valve and the feed control valve 18 may be configured as a basicopen/close valve. In a further embodiment, the system 2 may include abypass control valve 16 only (i.e., the feed control valve 18 may beomitted).

In various embodiments, one or more heating elements (not shown) may beoperatively associated with any or all of the components of the flowpath 6, including the bypass and feed control valves 16, 18. The heatingelements may be utilized to, for example, maintain the temperature ofthe conduits 6 a, 6 b, and 6 c and/or valves 16, 18 at a temperatureabove a condensation point of a vapor being transported therethrough,thereby preventing condensation of the vapor on the walls of theconduits 6 a, 6 b, and 6 c and/or valves 16, 18.

In some embodiments, the system 2 may include a controller 22operatively coupled to one or more components of the system 2 such thatone or more characteristics of a fluid flow within the fluid pathway 6may be monitored and/or controlled. Generally, the controller 22 may beconfigured as one or more processing devices (e.g., general purposecomputers, programmable logic controllers, combinations thereof) havinginstructions stored thereon for monitoring system variables and causingcomponents of the system 2 to perform specified functions. For example,the controller 22 may be provided with instructions to, in response tosignals received from one or more components of the system 2 (e.g.,sensors) selectively actuate one or more components of the system 2(e.g., valves) to achieve/maintain a desired process condition (e.g.,flow rate, pressure setpoint) within the fluid pathway 6.

In various embodiments, as shown in FIG. 1, the controller 22 may beoperatively coupled to any or all of the pressure sensor 14, the bypasscontrol valve 16, and the feed control valve 18. In this embodiment, thecontroller 22 may be provided with instructions to, for example, receivesignals from the pressure sensor 14 regarding a fluid pressure withinthe fluid pathway 6, compare the measured pressure to a predeterminedpressure setpoint, and selectively actuate either or both of the bypasscontrol valve 16 and the feed control valve 18 (e.g., set/change valveposition) such that the pressure setpoint is achieved/maintained. Inthis manner, the system 2 may be configured to precisely control systempressures and flow rates, such as the pressures and flow rates of vaporentering the first vacuum chamber 8 and/or the second vacuum chamber 12.Consequently, and as will be discussed in further detail below, thesystem 2 may also be configured to compensate for any interruptions orperturbations in the rate of vapor supplied by the vapor source 4.

In various embodiments, the first vacuum chamber 8 may include anydevice configured to condense and collect a vapor flow under vacuumconditions. In this regard, the first vacuum chamber 8 may be operatedat a temperature and pressure sufficient to condense any or all of thecomponents of a vapor flow which is transported from the vapor source 4to the first vacuum chamber 8. To achieve a vacuum pressure, the firstvacuum chamber 8 may be operatively coupled to one or more vacuumsources, such as a vacuum pump 26. In one embodiment, the first vacuumchamber 8 may include a condenser having a collector disposed thereinfor collecting condensed vapor.

In illustrative embodiments, the second vacuum chamber 12 may includeany device configured to condense, under vacuum conditions, at least aportion of a vapor flow introduced to the chamber 12 through the feedconduit 6 c. To achieve a vacuum pressure, the second vacuum chamber 12may be operatively coupled to one or more vacuum sources, such as avacuum pump 28.

In one embodiment, the second vacuum chamber 12 may include a condensingchamber (e.g., a vacuum distillation chamber) that includes a collectorfor collecting condensed vapor and optionally an outlet for releasingany uncondensed vapor. In such an embodiment, the second vacuum chamber12 may be operated under conditions (e.g., temperature and pressure)such that pressure within the vacuum chamber 12 is at or above the vaporpressure of one or more components of a vapor mixture that is beingtransported to the vacuum chamber 12 from the feed vapor conduit 6 c. Inthis manner, one or more components of the vapor mixture may becondensed out of a vapor mixture and collected in a collector. Infurther embodiments, the conditions of the second vacuum chamber 12(e.g., temperature and pressure) may be different than that of the firstvacuum chamber 8. In this way, one or more first components of a vapormixture being transported to the vacuum chamber 12 via the fluid pathway6 may be condensed and collected in the vacuum chamber 12, and one ormore second components, which differ from the first components, may becondensed and collected in the first vacuum chamber 8.

In another embodiment, and as depicted in FIG. 1, the second vacuumchamber 12 may include a vapor coater for depositing at least a portionof a vapor flow on a substrate. Generally, vapor coaters useful in thesystem 2 of the present disclosure may include a rotating process drumand a plurality of rollers configured for unwinding a substrate (e.g., arolled web of material), passing the un-wound substrate over a surfaceof the process drum, and re-winding the substrate. Useful vapor coatersmay also include a vapor nozzle, in fluid communication with a vaporsource, configured to deposit (e.g., by condensation, CVD reaction,plasma deposition) a vapor onto a surface of the substrate as it ispassed over a surface of the process drum.

As shown in FIG. 1, in one embodiment, a vapor coater for use in thesystem 2 may include a first roll 32 configured to direct a substrate 34around a rotatable process drum 36, and a second roll 38 configured tore-wind the substrate. The vapor coater may further include one or morevapor nozzles 42 positioned proximate a surface 43 of the rotatableprocess drum 36. The vapor nozzles 42 may be configured todeposit/condense a vapor onto a surface of the substrate 34 as it ispassed over the process drum 36. In this regard, the vapor nozzles 42may be fluidically coupled to the fluid pathway 6, particularly, thevapor feed conduit 6 c. The rotatable process drum 36 may be providedwith a heat transfer fluid circulation such that at least the surface 43is temperature controlled, thereby promoting condensation, reaction,and/or other form of deposition of vapor onto the substrate 34.

In some embodiments, the vapor coater may further include one or morecuring sources 44. The curing sources 44 may be positioned within thevapor coater such that following vapor deposition/condensation, thesubstrate 34 may be exposed to a treatment delivered from the curingsources 44. Curing sources 44 useful in the systems of the presentdisclosure include one or more of, for example, heat sources,ultraviolet radiation sources, e-beam radiation sources, and plasmaradiation sources.

In various embodiments, the vapor coater may, in addition to the one ormore vapor coating processes, include other deposition processes. Forexample, sputtering may precede or follow one or more vapor depositingsteps to deposit layers such as, for example, metals, metal oxides,metal nitrides, and ceramics. Metals suitable for deposit by sputteringinclude, for example, aluminum, nickel, silver, chrome, copper, andcombinations thereof. Metal oxides suitable for deposit by sputteringinclude, for example, alumina, magnesia, silica, zirconia, and titania.

Suitable substrates 34 for use in the vapor coater described hereininclude flexible materials capable of roll-to-roll processing, such aspaper, polymeric materials, metal foils, and combinations thereof.Suitable polymeric substrates include various polyolefins, e.g.polypropylene, various polyesters (e.g. polyethylene terephthalate,fluorene polyester), polymethylmethacrylate and other polymers such aspolyethylene naphthalate, polyethersulphone, polyestercarbonate,polyetherimide, polyarylate, polyimide, vinyls, cellulose acetates, andfluoropolymers.

In an alternative embodiment, the substrate 34 is a discrete part ratherthan a continuous roll of film. The discrete part may move past thevapor nozzle 42, or the discrete part may be stationary during thecoating process. Suitable discrete substrates include silicon wafers,electronic or optical devices, glass, metal, and plastic parts.

The present disclosure further relates to methods for processing vaporsuch as, for example, monitoring and controlling a flow of vaporgenerated by a vapor source. The methods for processing vapor may becarried out utilizing the system of FIG. 1.

In some embodiments, the methods of the present disclosure may include,during normal operation, discharging vapor from the vapor source 4 intothe outlet conduit 6 a at an initial vapor flow rate. The initial flowrate of the vapor may be substantially equivalent to a current vaporgeneration rate of the vapor source 4 (e.g., the vapor generated by thevapor source 4 may be vented to the outlet conduit 6 a). The vapor flowmay then be transported, at the initial rate, through the outlet conduit6 a towards the vapor bypass control valve 16 and the feed control valve18. The controller 22, via its coupling to one or more pressure sensors(e.g. pressure sensor 14), may monitor the pressure of the vapor at aposition within the fluid pathway 6. The positions of the bypass controlvalve 16 and the feed control valve 18 may be such that, at the initialvapor flow rate, a pressure within the fluid pathway 6 is at apredetermined pressure setpoint. Assuming the positions of the bypasscontrol valve 16 and the feed control valve 18 are maintained (andconstant temperature), at the initial vapor flow rate, the pressuresetpoint may be maintained within the fluid pathway 6. Moreover, theflow rates of vapor through the fluid pathway 6, including the vaporbypass conduit 6 b and the vapor feed conduit 6 c, may be substantiallymaintained at an initial value.

The vapor generation rate of the vapor source 4 may fluctuate, therebycausing a momentary increase/decrease of the vapor flow rate andpressure within the outlet conduit 6 a and, in turn, the bypass conduit6 b and the feed conduit 6 c. The controller 22 may detect thisvariation in vapor flow conditions, for example, by signals receivedfrom the pressure sensor 14. Upon detection of the variation in flowconditions, the controller 22 may communicate instructions to either orboth of the bypass control valve 16 and the feed control valve 18 tochange their respective positions. Particularly, the controller 22 mayeffect modulation of the positions of either or both of the bypasscontrol valve 16 and the feed control valve 18 such that the pressureand flow rate of vapor passing through the feed conduit 6 c ismaintained (and thus the pressure and flow rate of vapor passing throughthe bypass conduit 6 b is varied), despite the variation in vapor flowsupplied by the vapor source 4. The controller 22 may accomplish thisby, for example, modulating the positions of either or both of thebypass control valve 16 and the feed control valve 18 such that the apressure of the vapor at a position within the flow system 6 ismaintained at the predetermined pressure set point. In this manner, thesystems and methods of the present disclosure may allow for precisecontrol of the pressure and flow rates of vapor passing through thebypass conduit 6 b and the feed conduits 6 c.

In some embodiments, the controller 22 may control the amounts andpressures of vapor passing through the fluid pathway 6, particularly,the bypass vapor and feed vapor conduits 6 b, 6 c, by modulating theposition of the bypass control valve 16 only (and thus maintaining thefeed control valve 18 in a fixed position). In such embodiments, uponthe controller 22 detecting a variation in vapor flow conditions, thecontroller 22 may modulate the position of the bypass control valve 16such that the flow rate and pressure of the vapor passing through feedvapor conduit 6 c is maintained. The controller 22 may accomplish thisby, for example, modulating the positions of the bypass control valve 16such that the pressure of the vapor flow at a position within the flowsystem 6 (e.g., pressure in outlet conduit 6 a) is maintained at apredetermined pressure set point. In embodiments in which vapor flow iscontrolled by modulation of the bypass control valve 16 only, the feedcontrol valve 18 may be configured as an on/off valve or omitted.

In embodiments in which the second vacuum chamber 12 is a vapor coater,the methods of the present disclosure further include deposition of atleast a portion of the vapor transported into the vacuum chamber 12 fromthe feed conduit 6 c onto a substrate. Referring again to FIG. 1, themethod may include unwinding the substrate 34 from the first roll 32 andonto the surface 43 of the process drum 36, such that the substrate 34is in intimate contact with the drum surface 43. As the process drum 36rotates, the substrate 32 may move past the vapor nozzle 42. The vapornozzle 42 may project vapor, which is being supplied at a preciselycontrolled pressure and flow rate through the feed conduit 6 c, onto thesubstrate 34 where it may deposited by, for example, condensation, CVDreaction, or plasma deposition. As the process drum 36 is furtherrotated, condensed fluid deposited on the substrate 34 may move past thecuring source 44, which may apply a curing treatment to form a curedcoating layer on the substrate. The coated substrate may then bere-wound on the second roll 38.

Utilizing the vapor monitoring and control methods of the presentdisclosure outlined above, the flow rate and pressure of the vapor beingtransported in the feed conduit 6 c and, thus the deposition rate ontothe substrate 34, may be precisely controlled irrespective offluctuations or perturbations in the rate vapor is being supplied fromthe vapor source 4. Consequently, the vapor may be deposited onto thesubstrate 34 with very small variations in thickness over the length ofthe substrate 34. Moreover, by incorporating a bypass conduit 6 b intothe fluid pathway 6, flow of vapor to the vapor coater may be eliminatedduring start up and shut down phases of the vapor source 4, therebyreducing the amount of substrate wasted during the start up and shutdown phases.

In embodiments in which the second vacuum chamber 12 is a condensingchamber, the methods of the present disclosure further includecondensing at least a portion of the vapor transported into the vacuumchamber 12 from the feed conduit 6 c. For example, the method mayinclude operating the condensing chamber at a pressure that is above thevapor pressure of any or all of the components of the vapor beingtransported from the vapor feed conduit 6 c, condensing at least aportion of the vapor, and collecting the condensed vapor in a collector.

In some embodiments, the vapor processing systems and methods of thepresent disclosure may be carried at pressures within the fluid pathway6 as low as 1000 mTorr, 100 mTorr, 1 mTorr, 0.1 mTorr, or even as low as0.001 mTorr. Pressures within the fluid pathway 6 may be as high as 1Torr, 10 Torr, 100 Torr, 500 Torr, or even as high as 760 Torr.

In various embodiments, the vapor processing systems and methods of thepresent disclosure may be carried at vapor flow rates as low as 1 g/min,0.1 g/min or even as low as 0.001 g/min. The vapor flow rates may be ashigh as 100 g/min, 1 kg/min, or even as high as 50 kg/min. In oneembodiment, the vapor flow rate ranges from 1-50 g/min.

In embodiments in which the second vacuum chamber 12 includes a vaporcoater, the systems and methods of the present disclosure may be run atsubstrate line speeds as low as 10, 1, or even as low as 0.1 feet/minute(3.0, 0.3 or 0.03 m/min.). Substrate line speeds may be as high as 10,100, or even as high as 2000 feet/minute (3.0, 30.5 or 609.6 m/min.). Inone embodiment, the substrate line speed ranges from 10-300 feet/minute3.0-304.8 m/min.).

In embodiments in which the second vacuum chamber 12 include a vaporcoater, the systems and methods of the present disclosure may achievecoating thicknesses as low as 100, 10, or even as low as 0.1 nm. Thecoating thicknesses may be as high as 1, 25, or even as high as 50 μm.In one embodiment, the coating thicknesses may range from 0.1-10,000 nm,1-5000 nm, or 10-1000 nm.

As previously discussed, the system and methods of the presentdisclosure allow for precise control of the pressures and flows of vaporentering the second vacuum chamber 12 and, thus in embodiments in whichthe second vacuum chamber 12 includes a vapor coater, precise control ofthe deposition rate of the vapor onto a substrate. Such precise controlof deposition rate, in turn, allows for the deposition of coatingshaving very small variations in thickness over the length of thesubstrate (i.e, the longitudinal dimension of the substrate). In someembodiments, the systems and methods of the present disclosure mayproduce coated substrates having a variation in coating thickness ofless than 20%, 5%, or even less than 1% over lengths of substrate ashigh as 10, 1000, or even as high as 10,000 feet.

The systems and methods of the present disclosure may be used to producesingle or multi-layer films for applications such as optical films(reflectors, antireflection, absorbers, colored, optically variable,optical filters, optical interference filters, infrared reflectors), EMI(Electromagnetic Interference) filters, release coatings, transparentconductive films, capacitors, sensors, heat seal packaging, and displayfilms. Examples of at least some of such films are described in thefollowing patents and publications, incorporated by reference herein intheir entireties: U.S. Pat. No. 5,018,048 (Shaw et al.); U.S. Pat. No.5,811,183 (Shaw et al.); U.S. Pat. No. 5,877,895 (Shaw et al.); U.S.Pat. No. 6,172,810 (Fleming et al.); U.S. Pat. No. 6,815,043 (Fleming etal.); U.S. Pat. No. 6,818,291 (Funkenbusch et al.); U.S. Pat. No.6,929,864 (Fleming et al.); U.S. Pat. No. 6,357,880 (Epstein et al.);2005/0037218 (Lottes et al.); U.S. Pat. No. 7,449,146 (Rakow et al.);U.S. Pub. No. 2006/0078700 (Blestos et al.) and 2003/0124392 (Bright).

The systems and methods of the present disclosure may further be used toproduce coated substrates which, when combined with additional layersof, for example, metals or metal oxides, limit permeation of gases suchas oxygen and water vapor. Such barrier films and processes for thepreparation of barrier films may be found, for example in the followingpatents and publications, incorporated by reference herein in theirentireties: U.S. Pat. No. 5,440,446 (Shaw, et al.); U.S. Pat. No.5,725,909 (Shaw et al.); U.S. Pat. No. 6,231,939 (Shaw et al.); U.S.Pat. No. 6,420,003 (Shaw et al.); U.S. Pat. No. 4,647,818 (Ham); U.S.Pat. No. 4,696,719 (Bischoff); U.S. Pat. No. 4,842,893 (Yializis etal.); U.S. Pat. No. 4,954,371 (Yializis); U.S. Pat. No. 5,032,461 (Shawet al.); U.S. Pub. 2002/0022156 (Bright), U.S. Pat. No. 7,018,713(Padiyath et al.), U.S. Pub. 2004/0202708 (Roehrig et al.), and U.S.Pub. 2005/0037218 (Lottes et al.). Such moisture and oxygen resistantbarrier films are useful in the manufacture of many products, forexample, as packaging for food and drugs and for the protection ofenvironmentally sensitive electronic devices. Electronic devices thatdegrade when exposed to environmental moisture and oxygen are oftenprotected from exposure by encasing the device in glass. A particularlyuseful application of barrier films made by the process disclosed hereinincludes protection for electronic display and signage devices, such asliquid crystal displays (LCDs), light emitting diodes (LEDs), organiclight emitting diodes (OLEDs), light emitting polymers (LEPs),electrochromic, electrophoretic inks, inorganic electroluminescentdevices, phosphorescent devices, and the like. Other useful applicationsfor barrier films produce at least in part by the systems and methods ofthe present disclosure include the protection of solar cells,photovoltaics, micro-electronics, organic micro-electronic devices(OMED), nano-devices, and nano-structures. Still other usefulapplications for such barrier films include bio-active devices such asthose used in analytical measurements of bio-active materials,bio-active-micro-electronic devices used for analysis or separations. Inaddition to providing a barrier to environmental moisture and oxygen,the barrier films may be flexible, making possible the production offlexible displays, electrical devices, and bio-active devices.

EXAMPLES

The operation of the present disclosure will be further described withregard to the following detailed examples. These examples are offered tofurther illustrate the various specific and preferred embodiments andtechniques. It should be understood, however, that many variations andmodifications may be made while remaining within the scope of thepresent disclosure.

Examples 1-5

A coating precursor solution of difunctional acrylate monomer (SR833Sfrom Sartomer) and 250 ppm of a polymerization inhibitor (as describedgenerally in U.S. Pub. 2010/0168434, which is incorporated herein byreference in its entirety) was vaporized and coated at a coating widthof 12.5 inches (318 mm) onto a substrate (2-mil (51 μm) PET, 14-inches(356 mm) wide) as follows.

The coating precursor solution was placed in a temperature controlledsupply tank and preheated to a temperature of 100° C. The coatingprecursor solution was fed, using a liquid flow controller, from thesupply tank to a vapor source, as generally described in the presentdisclosure, at a rate of 8.0 ml/min (it is believed that the type ofvapor source does not have an appreciable impact on coatingperformance). The vapor source was vented to a fluid conduit thatseparated the vapor flow into 2 channels: a bypass conduit connected toa condenser (operated at −10° C.) and a feed conduit connected to avapor nozzle of a vapor coater (configured similarly to the vapor coaterdescribed with respect to FIG. 1 of the present disclosure). A vaporcontrol valve (Baumann 81000 Mikroseal Control Valve with FieldVUEDCV2000 Digital Valve Controller from Emerson Process Management) wasprovided in the bypass conduit, and a shut-off valve was provided in thefeed conduit. The fluid conduit, including the bypass and feed conduits,shut-off valve, and vapor control valve were heated to 181° C. Thepressure of the vapor flow was measured in the fluid conduit (upstreamof the bypass and feed conduits) using an MKS Baratron capacitancemanometer. The manometer supplied feedback into the vapor control valvefor process control.

The coating precursor was discharged from the nozzle onto the substratetravelling at a constant line speed (16 feet per minute (4.9 m/min.)).The process drum temperature was maintained at 0° C. The substrate wassubsequently passed under an electron beam operating at 9.0 kV and 4.0mA to effect curing. The coating thickness was controlled using thevapor control valve to regulate the pressure of vapor in the fluidconduit. The vapor control valve was programmed to maintain a pressuresetpoint in the fluid conduit, and different pressure setpoints wereselected as listed in Table 1. The transmission and reflectance of thecoating and the substrate were measured at a downstream location usingan online optical spectrophotometer. Thickness was determined based uponthe location of interference peak maxima and minima across the spectrumfrom 400 to 850 nm measured using the spectrophotomer.

TABLE 1 VAPOR PRESSURE AND COATING THICKNESS Pressure Set Point MeanCoating Thickness Example (mtorr) (nm) 1 80 592 2 90 722 3 100 842 4 110967 5 93 735

FIG. 2 illustrates a plot of the mean coating thickness versus pressureset point observed in Examples 1-5. A linear relationship between thevapor pressure and the coating thickness was observed:

Thickness(microns)=0.0125*(Vapor Pressure)−0.4118(R ²=0.9959)

Example 6

A coating precursor solution of difunctional acrylate monomer (SR833 S)and 250 ppm of a polymerization inhibitor was vaporized and coated at acoating width of 12.5 inches (318 mm) onto a substrate (2-mil (51 μm)PET, 14-inches (356 mm) wide) as in Examples 1-5, except that: 4 wt % ofN-n-Butyl-Aza-2,2-Dimethoxysilacyclopentane (Gelest) was added to theprecursor formulation; the electron beam was operated at 7.0 kV and 3.0mA; and the vapor control valve was operated to maintain the pressure at95 mtorr.

FIG. 3 is a plot of both vapor pressure and measured coated thickness,as a function of substrate web position in a longitudinal, or down-webdirection, observed in Example 6. The mean thickness was 771 nm with astandard deviation of 14.8 nm. The coefficient of variance (COV) was0.019, substantially less than the COV of the liquid flowrate into thevapor source (liquid flowrate mean 7.90 ml/min, standard deviation 0.334ml/min, COV 0.042). This demonstrates that the vapor control valvesubstantially reduced the variation in the coating thickness relative tothe variation in the input flow rate of the liquid.

Other embodiments of the invention are within the scope of the appendedclaims.

What is claimed is:
 1. A method for controlling flow of a vaporcomprising: discharging a vapor from a vapor source into a conduitconnected to the vapor source, wherein downstream of the vapor sourcethe conduit separates into two conduits, a vapor bypass conduit and avapor feed conduit; providing a first vapor control valve disposed inthe bypass conduit, a controller operatively connected to the firstvapor control valve, a first vacuum chamber connected to the bypassconduit and disposed downstream of the first vapor control valve, and asecond vacuum chamber connected to the feed conduit; and controlling theflow of vapor passing through the bypass conduit by manipulation of thefirst vapor control valve.
 2. The method of claim 1, in which there isalso provided in the feed conduit upstream of the second vacuum chambera second valve and during part of carrying out of the method, vapor flowin the feed conduit is prevented by closing the second valve.
 3. Themethod of claim 1 in which the second vacuum chamber comprises a vaporcoater, the vapor coater comprising a temperature-controlled surface, avapor dispensing nozzle connected to the vapor feed conduit and disposedproximate the temperature-controlled surface and a plurality of rollersconfigured for passing a substrate web around the atemperature-controlled surface; and the method further comprises thesteps of discharging the vapor from the dispensing nozzle; anddepositing the vapor on a surface of the substrate web to form acoating.
 4. The method of claim 3, in which the vapor is deposited onthe surface of the substrate web by one or more methods selected fromthe group consisting of condensation, chemical vapor deposition, andplasma deposition.
 5. The method of claim 3 further comprising curingthe coating.
 6. The method of claim 3, wherein the coating is depositedat a mean thickness between 0.01 and 1.0 μm.
 7. The method of claim 1 inwhich the operating temperature and/or pressure conditions of the firstand second vacuum chambers are different, and conditions in the firstvacuum chamber cause one or more components of the vapor to be condensedand collected in the first vacuum chamber.
 8. The method of claim 1 inwhich the second vacuum chamber further comprises a vacuum distillationchamber for condensing at least a portion of the vapor, the methodfurther comprising collecting condensed vapor in a collector within thevacuum distillation chamber.
 9. The method of claim 1 further comprisingadding to the vapor in the conduit a gas selected from nitrogen, argon,helium, neon, oxygen, ozone, nitrous oxide, hydrogen, hydrogen sulfide,carbon tetrafluoride, methane, ammonia and combinations thereof.